Commercial, industrial, and household waste, e.g. (rigid) plastics, textiles, composites, rubber and used wood (such as pallets and chipboard), needs to be reduced in size before its final disposal or in particular before return to the recycling system. For shredding single or multi-shaft shredding machines are known, which for example are charged by wheel loaders, fork-lift trucks or conveyor belts via a hopper for charging material.
A central element of a conventional shredding machine is a rotor unit, which comprises a rotor which is fitted with tearing hooks or blades, which, for example, can be provided with concavely ground round cutter crowns. The blades are mounted for example by screwing onto blade bearers which are welded into or bolted onto blade pockets milled into the rotor. The shredding of the charged material occurs between the blades turned by the rotor and stationary, i.e. non-rotating, counter-blades (stator blades, scraper combs).
The charged material can, for example, be pressed in the direction of the rotating rotor by, for example, a pusher device controlled dependent on the load. After shredding between the rotating blades and the counter-blades, the material is output through a sieve device which determines the reduction factor according to the specification of the sieve size and conveys the material further with the aid of a conveyor belt, conveying screw, chain conveyor or suction system.
In particular with waste products of lower specific density or also with waste products too large to be conveyed, pressing of the material to be shredded towards the rotor is essential for shredding or at least necessary for commercial efficiency with regard to the throughput rate.
In the state of the art (DE 40 26 795 C3) a draw-type pusher (slide) for a scrap-wood shredding machine is known which comprises a press stamp which in turn has a press platen which presses the scrap wood towards the rotor horizontally or at a finite angle to the horizontal of the overall structure. A draw-type pusher of this nature is built into the shredding device supported on guides. These guides however inevitably become soiled in the course of the shredding operation and this can interfere with proper shredding operation. In addition the draw-type pusher increases the space required by the shredding device.
In an alternative embodiment the pusher device is installed pivotable and not completely integrated in the charging and shredding space of the shredding device, but rather has a press platen which is passed through an aperture in the hopper wall and which is movable parallel to the rotor (refer to AT 402 804 B). Also with this embodiment the space requirement is disadvantageously relatively high. In addition the sealing of the compression element passed through the aperture is problematical, because even if the press platen is pivoted without guidance for compression, waste products can gain access to the edges of the aperture, thus severely hindering the pushing process.
Thus, with regard to the problems mentioned an objective of the present invention is to make an improved shredding device with a pusher device available which requires the least possible space, and the reliability and operational efficiency of which is not or at least to a slighter extent impaired than as known in the state of the art through the impairment of the pushing process due to waste products to be shredded.